Question: Gabriela did 9 more sit-ups than Luis in the morning. Gabriela did 36 sit-ups. How many sit-ups did Luis do?
Answer: Gabriela did 36 sit-ups, and Luis did 9 fewer than that, so find the difference. The difference is $36 - 9$ sit-ups. She did $36 - 9 = 27$ sit-ups.